1. Field of the Invention
The present invention relates to a terminal that supports video conferencing, and more particularly to, a terminal in which communication parameters of the Moving Picture Experts Group (MPEG)-4 scheme is registered in a control protocol for supporting video teleconferencing. The present application is based on Korean Application Number 1999-47515, which is incorporated herein by reference.
2. Description of the Related Art
In order to realize a video teleconferencing system, the International Telecommunications Union (ITU) developed the Recommendations H.323 and H.324M. The Internet Engineer Task Force (IETF) recommends the media gateway control protocol (MGCP) for supporting packet-based video data communications over the Internet. Development of MPEG-4 related standards such as the International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) 14496 allows for enhanced video data processing. However, a conventional terminal has not yet supported the MPEG-4 standard. Thus, a terminal that supports video conferencing is required to support the MPEG-4 standard.
To solve the above problems, it is an object of the present invention to provide a terminal that supports signaling used in transmission and reception of the Moving Pictures Experts Group (MPEG)-4 data in order to apply the signaling to MPEG-4 video data, audio data and system data.
Accordingly, to achieve the above object, a terminal according to the present invention includes a video codec for performing video coding/decoding, an audio codec for performing audio coding/decoding, a multiplexer for performing multiplexing on encoded data, and a system controller for performing signaling for negotiating the terminal capability. The system controller includes: a video capability registration unit for registering a plurality of parameters for determining video capability, at least one of which is a parameter for determining video capability that conforms to the Moving Picture Experts Group (MPEG)-4 standard; an audio capability registration unit for registering a plurality of parameters for determining audio capability, at least one of which is a parameter for determining audio capability that conforms to the MPEG-4 standard; and a system capability registration unit for registering a plurality of parameters, at least one of which is a parameter for determining system capability that conforms to the MPEG-4 standard.
The parameters for determining the video capability, audio capability, and system capability that conform to the MPEG-4 standard are each defined in the standards International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC) 14496-2, ISO/IEC 14496-3, and ISO/IEC 14496-1. Furthermore, assuming that the terminal complies with the H.323 standard, which is a video teleconferencing system related standard defined by the International Telecommunication Union-Terminal Sector (ITU-T), the system controller is based on the H.245 standard which specifies a control protocol in the system related standard. Alternatively, the system controller may be based on the session description protocol (SDP) in the media gateway control protocol (MGCP) for supporting packet-based video data communications over the Internet, which is defined by the Internet Engineer Task Force (IETF).
In order to determine a visual profile that conforms to the MPEG-4 standard and the level of the visual profile, the video capability registration unit defines a protocol element comprising at least one among the parameters profileAndLevel-NBitL2, profileAndLevel-MainL4, profileAndLevel-MainL2, profileAndLevel-CoreL2, profileandLevel-CoreL1, profileAndLevel-SimpleScalable, profileAndLevel-SimpleL3, profileandLevel-SimpleL2, and profileAndLevel-SimpleL1 corresponding to NBitL2, MainL4, MainL2, CoreL2, CoreL1, SimpleScalable, SimpleL3, SimpleL2, and SimpleL1 which are visual profiles defined by the ISO/IEC 14496-2 standard which conforms to MPEG-4 Version 1. In this case, the parameters are defined as xe2x80x9cBOOLEANxe2x80x9d, and one of the parameters is selectively registered.
Furthermore, the video capability registration unit defines a protocol element further comprising at least one of a parameter typicalVisualSessionSize for determining a session size, a parameter maximumTotalNumberOfObjects for determining a maximum number per type, a parameter maximumNumberDifferentQuantization-Table for determining the maximum number of different quantization tables, a parameter maxTotalReferenceMemory for determining the maximum capacity of a reference memory, a parameter maximumNumberOfMBsec for determining the maximum number of macroblocks transmitted per second, a parameter costFunctionEquivalent for determining the number of macroblocks transmitted per second, a parameter maximumVBVBuffer-Size for determining the maximum buffer size of a video buffer verifier (VBV), a parameter maxVideoPacketLength for determining the length of a video packet, a parameter for determining the size of background image, a parameter wavelet-Restrictions for determining the characteristic of a wavelet filter, a parameter maxBitrate for determining a maximum bit rate, and a parameter maxEnhancement-LayersPerObject for determining the maximum number of enhancement layers per object, which is defined by the ISO/IEC 14496-2 which conforms to MPEG-4 Version 1.
In order to determine an audio profile and the level of the audio profile which conform to the MPEG-4 standard, the audio capability registration unit defines a protocol element comprising at least one of the parameters profileAndLevel-MainL4, profileAndLevel-MainL3, profileAndLevel-MainL2, profileAndLevel-MainL1, profileAndLevel-ScalableL4, profileAndLevel-ScalableL3, profileAndLevel-ScalableL2, profileAndLevel-ScalableL1, profileAndLevel-SpeechL2, profileAndLevel-SpeechL1, profileAndLevel-SynthesisL3, profileAndLevel-SynthesisL2, and profileAndLevel-SynthesisL1 corresponding to MainL4, MainL3, MainL2, MainL1, ScalableL4, ScalableL3, ScalableL2, ScalableL1, SpeechL2, SpeechL1, SynthesisL3, SynthesisL2, and SynthesisL1 which are audio profiles defined in the ISO/IEC 14496-1 which conforms to MPEG-4 Version 1. In this case, the parameters are defined as xe2x80x9cBOOLEANxe2x80x9d, and one of the parameters is selectively registered.
Furthermore, preferably, the audio capability registration unit defines a protocol element further comprising at least one of a parameter pcu for denoting a processor complexity unit in mega operations per second (MOPS) times 1, and a parameter rcu for denoting a RAM complexity unit, which are defined in the ISO/IEC 14496-1 which conforms to MPEG-4 Version 1.
Preferably, the audio capability registration unit defines a protocol element further comprising at least one of the parameters audioSamplingl6 k, audioSampling22.05 k, and audio Sampling48 k for determining audio sampling frequency, the parameters being defined in the ISO/IEC 14496-1 which conforms to MPEG-4 Version 1.
Preferably, the audio capability registration unit defines a protocol element further comprising at least one of a parameter numberOfMonoObjects for determining the number of mono objects, a parameter numberOfStereoObjects for determining the number of stereo objects, and a parameter numberOfSpeech-Objects for determining the number of speech objects which are defined in the ISO/IEC 14496-1 which conforms to MPEG-4 Version 1.
Preferably, the audio capability registration unit defines a protocol element further comprising at least one of a parameter memoryForData for determining the size of data memory, parameters lowProcessing and highProcessing, which are reserved in association with complexity, and a parameter numberOfTTSIObjects for determining the number of text-to-speech information (TTSI) objects which are defined in the ISO/IEC 14496-1 which conforms to MPEG-4 Version 1.
In order to determine an MPEG compliant system profile and the level of the system profile, a plurality of parameters defined in the ISO/IEC 14496-1, which conforms to MPEG-4 Version 1, are defined as xe2x80x9cBOOLEANxe2x80x9d, thereby registering one selected from the plurality of parameters. The video codec and the audio codec comprise an MPEG-4 video codec means for performing video coding/decoding, and an MPEG-4 audio codec means for performing audio coding/decoding. The MPEG-4 video codec means and MPEG-4 audio codec means perform the video and audio coding/decoding defined in the ISO/IEC 14496 standard.